The U.S. Transportation Security Administration has said it may ask air travelers headed to the U.S. on direct flights to power up some electronic devices, including cell phones, as part of enhanced security measures at certain airports abroad.

Under the regulations announced Sunday, powerless devices will not be permitted on board the aircraft and the traveler may also undergo additional screening, TSA said.

The new measures come in the wake of reports that terrorists are working on using electronic devices as bombs. TSA did not provide specific reasons why the new measures were being introduced. “As the traveling public knows, all electronic devices are screened by security officers,” it said in a statement.

Jeh Johnson, secretary of Homeland Security, said last week that the TSA had been directed to introduce enhanced security measures in the coming days at certain overseas airports with direct flights to the U.S. “DHS continually assesses the global threat environment and reevaluates the measures we take to promote aviation security,” Johnson said in a statement.

The TSA did not disclose the airports abroad where the restriction on powerless electronic devices will come into force.